Heterogeneity of outcomes of endometrial cancer patients included in prospective clinical trials.

Objective: To assess heterogeneity in five-year overall survival of patients with endometrial cancer using a large retrospective database with cohorts defined by recent prospective clinical trials.
Methods: The National Cancer Database was used to identify patients with endometrial cancer who underwent hysterectomy from 2004 to 2016. The reported inclusion criteria for GOG-249, PORTEC-3, and GOG-258 were used to define the respective cohorts. Five-year overall survival for each cohort was stratified by tumor characteristics and adjuvant therapy regimens.
Results: A total of 89,133 patients were identified who would have fulfilled the entry criteria to GOG-249, PORTEC-3, or GOG-258. When stratified by tumor characteristics, irrespective of adjuvant therapy, five-year overall survival ranged from 59.9%-81.7% for patients meeting GOG-249 inclusion criteria, 40.2%-81.8% for patients meeting PORTEC-3 inclusion criteria, and 17.5%-75.0% for those meeting GOG-258 inclusion criteria. Analysis of subgroups by adjuvant therapy regimen revealed significant improvement in five-year overall survival for chemoradiotherapy compared to chemotherapy or radiotherapy alone for endometroid stage III and stage IVA disease and for some stages of serous and clear cell histology.
Conclusions: Recent prospective trials of adjuvant therapy for endometrial cancer have included heterogeneous cohorts of patients based on five-year overall survival rates when the populations are stratified by tumor characteristics. The variation in expected five-year overall survival for subsets of patients may result in underpowered studies or misleading results.
Competing Interests: Declaration of Competing Interest Dr. Wright received research support from Merck and honoraria from UpToDate.
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